Vibration damping device equipped with rubber heat-insulating cover

ABSTRACT

A vibration damping device having a rubber heat-insulating cover wherein the rubber heat-insulating cover is formed as a separate component from a stopper member and is disposed between the stopper member and a main rubber elastic body connecting a first and second mounting member. The rubber heat-insulating cover is fixed to the stopper member with a center section of the rubber heat-insulating cover juxtaposed from an inner face side against a strike plate portion of the stopper member to be supported by the strike plate portion. With a peripheral wall section of the rubber heat-insulating cover juxtaposed from the inner face side against leg portions of the stopper member to be supported by the leg portions. A cushioning rubber is integrally formed with the center section of the rubber heat-insulating cover supported on the strike plate portion, and projects towards the first mounting member.

INCORPORATED BY REFERENCE

The disclosure of Japanese Patent Application No. 2007-184970 filed onJul. 13, 2007 including the specification, drawings and abstract isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vibration damping device including: afirst mounting member fixable to a first component for vibration dampedconnection; a second mounting member fixable to another component; and amain rubber elastic body elastically connecting the first and secondmounting members. More specifically, the present invention is concernedwith a vibration damping device with a rubber heat-insulating cover,which is novel in structure having a rebound stopper mechanism forlimiting in a cushion-wise fashion an amount of displacement of thefirst mounting member and the second mounting member in the direction ofmutual separation, as well as a rubber heat-insulating cover forprotecting the main rubber elastic body from the effects of heat.

2. Description of the Related Art

Among vibration damping devices such as vibration damping connectionsand vibration damping supports adapted for interposition betweencomponents that make up a vibration transmission system, one type ofdevice proposed in the past has a structure which includes a firstmounting member fixable to a component intended for vibration dampedconnection, and a second mounting member fixable to another component,which members are elastically connected by a main rubber elastic body.Application of vibration damping devices having this structure asautomotive engine mounts, body mounts, or suspension bushings forexample, is the subject of ongoing research.

In order to exhibit good vibration isolating action, a vibration dampingdevice is desired to have sufficiently soft spring characteristics. Onthe other hand, upon input of large vibrational load, the vibrationdamping device is required to prevent large displacement of onecomponent and the other component which are connected in a vibrationdamping fashion. Consequently, in vibration damping devices, the firstmounting member and the second mounting member are provided typicallywith a stopper mechanism designed to limit the amount of their relativedisplacement.

JP-A-2005-172202 and JP-A-2004-276764 disclose one example of suchstopper mechanisms in the form of a rebound type stopper mechanism thatincludes an arched stopper member fastened at both of its leg sectionsto the second mounting member so as to straddle the first mountingmember in the axis-perpendicular direction, with the center section ofthe stopper member positioned in opposition in the axial direction tothe first mounting member and a cushioning rubber disposed on the faceof the center section of the stopper member in opposition to the firstmounting member. With this design, in the event that the first mountingmember and the second mounting member experience appreciabledisplacement in the direction of mutual separation (rebound direction)due to input of a large load, the amount of displacement of the firstand second mounting members in the rebound direction will be limited bythe stopper striking the first mounting member via the cushioningrubber.

However, where the cushioning rubber disposed on the stopper member, ifthe cushioning rubber and the center section of the stopper member areintegrally molded by vulcanization as taught in JP-A-2005-172202, itwill be necessary to provide a special mold for vulcanization moldingthat corresponds in design to the size and shape of the stopper member,or in the event of any design modification of the stopper member tomodify the design of the mold in association therewith. This results ina more complicated production process as well as limiting the degree offreedom in design of the cushioning rubber. Thus, this was not always aneffective approach for disposing the cushioning rubber on the stoppermember. It would also be possible, for example, to form the cushioningrubber as a separate component from the stopper member and to thensecure it to the stopper position of the stopper member. However, thiswould require a laborious positioning and fastening operation, and insome instances it was difficult to achieve sufficient stability offastening of the cushioning rubber.

Moreover, vibration damping devices furnished with a stopper mechanismof the sort described above are frequently employed in automotive enginemounts or other systems where they are exposed to input oflarge-amplitude vibration for example. A resultant problem is that ifthe main rubber elastic body is exposed directly to radiant heat orexhaust gases from an engine, its durability may decline to the pointthat it becomes difficult to obtain sufficient vibration damping actionbased on resilience of the main rubber elastic body.

One known measure for addressing this problem is a heat-insulatingcover-equipped vibration damping device having a heat-insulating cover(heat-insulating panel) disposed spacedly covering the outside surfaceof the main rubber elastic body so as to reduce the effects of outsideheat on the main rubber elastic body. Such a device is taught inJP-A-2004-276764, for example.

With the heat-insulating cover-equipped vibration damping deviceaccording to JP-A-2004-276764, the first mounting member is fastened toa mounting member on the power unit side, the cushioning rubber of thestopper member is disposed so as to strike the first mounting member viathe mounting member on the power unit side, and the center section ofthe rubber heat-insulating cover is supported on the first mountingmember. For this reason, within the limited space available to theinside of the arched stopper member, it was necessary to ensure a sitefor supporting the heat-insulating cover region, in addition to ensuringa site for fastening of the mounting member on the power unit side, butit was sometimes difficult to ensure sufficient room for both.Additionally, since a cushioning rubber with a separate structure mustbe affixed to the stopper member, a larger number of assembly steps wererequired, making it difficult to achieve improved production efficiency.

SUMMARY OF THE INVENTION

It is therefore one object of this invention to provide a vibrationdamping device equipped with a rubber heat-insulating cover, the devicebeing of novel design that affords ease of manufacture as well as stablepositioning of the rubber heat-insulating cover, and that enables acushioning rubber to be disposed with a high degree of freedom in designand in a reliable manner to the strike plate section of the stoppermember, to advantageously afford the desired heat insulation action andstopper action.

The above and/or optional objects of this invention may be attainedaccording to at least one of the following modes of the invention. Thefollowing modes and/or elements employed in each mode of the inventionmay be adopted at any possible optional combinations. It is to beunderstood that the principle of the invention is not limited to thesemodes of the invention and combinations of the technical features, butmay otherwise be recognized based on the teachings of the presentinvention disclosed in the entire specification and drawings or that maybe recognized by those skilled in the art in the light of the presentdisclosure in its entirety.

One aspect of the present invention provides a vibration damping devicehaving a rubber heat-insulating cover including: a first mounting memberfixable to one of components connected together in a vibration dampingfashion; a second mounting member fixable to an other of the components;a main rubber elastic body elastically connecting the first and secondmounting members; a stopper member of arched shape which includes a pairof leg portions at either end of a strike plate portion extending in anaxis-perpendicular direction, the stopper member being attached withlower ends of the pair of leg portions fastened to the second mountingmember so as to project outward from the first mounting member in orderto effect relative positioning of the strike plate portion and the firstmounting member; a cushioning rubber disposed on the strike plateportion on a face thereof in opposition to the first mounting member, toconstitute a rebound stopper mechanism for cushion-wise limitation of anamount of displacement of the first mounting member and the secondmounting member in a direction of mutual separation, through striking ofthe first mounting member and the strike plate portion via thecushioning rubber; and a rubber heat-insulating cover for covering anoutside face of the main rubber elastic body with a gap therebetween,disposed overlying the main rubber elastic body from the first mountingmember side, wherein the rubber heat-insulating cover is formed as aseparate component from the stopper member and is disposed between thestopper member and the main rubber elastic body while affixing therubber heat-insulating cover to the stopper member with a center sectionof the rubber heat-insulating cover juxtaposed from an inner face sideagainst the strike plate portion of the stopper member to be supportedby the strike plate portion, and with a peripheral wall section of therubber heat-insulating cover juxtaposed from the inner face side againstthe leg portions of the stopper member to be supported by the legportions, and the cushioning rubber is integrally formed with the centersection of the rubber heat-insulating cover supported on the strikeplate portion, and projects towards the first mounting member.

In the rubber heat-insulating cover-equipped vibration damping device ofstructure according to the present invention, since the cushioningrubber is formed as a separate component from the stopper member, itwill be possible to eliminate the need to prepare a specialvulcanization mold corresponding in design to the size and shape of thestopper member, or to modify the design of the mold in association witha design modification of the stopper member. Thus, the cushioning rubbermay be shaped easily, with a high degree of freedom in its design.

Furthermore, by integrally forming the cushioning rubber and the rubberheat-insulating cover together, vulcanization molding of the cushioningrubber and of the rubber heat-insulating cover can be accomplished witha single mold, thereby affording advantages in terms of manufacturingprocess efficiency and lower cost.

Additionally, since the center section and the peripheral wall sectionof the rubber heat-insulating cover are supported by the strike plateportion and the leg portions of the arch-shaped stopper member, therubber heat-insulating cover will be positioned reliably duringattachment to the vibration damping device. The rubber heat-insulatingcover will be retained in a stable fashion in the vibration dampingdevice, even with the device installed in the system targeted forvibration damping. This arrangement makes it possible to establish andconsistently maintain an appreciable distance separating the rubberheat-insulating cover and the outside face of the main rubber elasticbody, whereby the desired heat-insulating action will be advantageouslyachieved.

The cushioning rubber is integrally formed with the rubberheat-insulating cover having excellent stability of support on thestopper member, and is disposed on the strike plate portion of thestopper member in association with supporting of the rubberheat-insulating cover on the stopper member. Thus, the cushioning rubbermay be disposed reliably on the strike plate portion of the stoppermember without the use of any special fastening components, preventingany mispositioning thereof.

Moreover, the rubber heat-insulating cover is juxtaposed against thestopper member from the inner face side to be supported by the stoppermember. Thus, a space unobstructed by the rubber heat-insulating coverand allowing the cushioning rubber to project towards the first mountingmember will be advantageously ensured, thus affording a high degree offreedom in design of distance between the opposed faces of thecushioning rubber and the first mounting member.

The desired heat insulating action and stopper action will beadvantageously afforded thereby.

In the vibration damping device having the rubber heat-insulating coveraccording to the present invention, there may advantageously be employeda structure wherein catch hook portions are integrally formed in thecenter section and the peripheral wall section of the rubberheat-insulating cover, and a detaining slot which opens towards anoutside is formed in the strike plate portion and the pair of legportions of the stopper member so that a structure for supporting therubber heat-insulating cover on the stopper member is provided byengaging the catch hook portions with both walls of the detaining slot.With this structure, elastic deformation of the catch hook portionswhich have been integrally formed with the rubber heat-insulating covercan be utilized for the purpose of detaining the catch hook portions onthe two walls of the detaining slot.

Furthermore, in the rubber heat-insulating cover-equipped vibrationdamping device according to the present invention, there mayadvantageously be employed a structure wherein the rubberheat-insulating cover has an inverted cup shape and includes aninsertion slot formed extending along both peripheral wall portions froma bottom portion on an outside face of the rubber heat-insulating cover,and the stopper member is fitting into the insertion slot. Thisstructure utilizes the mating structure afforded by the insertion slot,whereby the rubber heat-insulating cover and the cushioning rubber maybe supported more stably on the stopper member, affording higheraccuracy of positioning.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and/or other objects features and advantages of theinvention will become more apparent from the following description of apreferred embodiment with reference to the accompanying drawings inwhich like reference numerals designate like elements and wherein:

FIG. 1 is a view integrally showing a front elevation and a sideelevation of a vibration damping device in the form of an automotiveengine mount according to one embodiment of the present invention;

FIG. 2 is a front elevational view of a stopper member of the automotiveengine mount of FIG. 1;

FIG. 3 is a top plane view of the stopper member of FIG. 2;

FIG. 4 is a side elevational view of the stopper member of FIG. 2;

FIG. 5 is a perspective view of a heat insulator of the engine mount ofFIG. 1;

FIG. 6 is a bottom plane view of the heat insulator of FIG. 5;

FIG. 7 is a top plane view of the heat insulator of FIG. 5;

FIG. 8 is a cross sectional view taken along line 8-8 of FIG. 7;

FIG. 9 is a cross sectional view taken along line 9-9 of FIG. 7;

FIG. 10 is a cross sectional view taken along line 10-10 of FIG. 7;

FIG. 11 is a cross sectional view taken along line 11-11 of FIG. 7;

FIG. 12 is a side elevational view of the heat insulator of FIG. 5;

FIG. 13 is a front elevational view of the heat insulator of FIG. 5;

FIG. 14 is a cross sectional view taken along line 14-14 of FIG. 13;

FIG. 15 is a cross sectional view taken along line 15-15 of FIG. 13;

FIG. 16 is a perspective view of a heat insulator and a stopper memberassembled together of an automotive engine mount according to anotherembodiment of the present invention;

FIG. 17 is a front elevational view of the heat insulator and thestopper member assembled together as shown in FIG. 16; and

FIG. 18 is a cross sectional view taken along line 18-18 of FIG. 17.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

First, in FIG. 1 there is shown an automotive engine mount 10 as oneembodiment of a rubber heat-insulating cover-equipped vibration dampingdevice of the present invention. This engine mount 10 has a structure inwhich a first mounting member 12 of metal and a second mounting member14 of metal are elastically connected via a main rubber elastic body 16;and a stopper member 18 of metal and a heat insulator 20 constitutingthe rubber heat-insulating cover are positioned with a space about thefirst mounting member 12 and the main rubber elastic body 16. This firstmounting member 12 is mounted onto the power unit side, while the secondmounting member 14 is mounted onto the vehicle body side to provide thepower unit with vibration damping support on the vehicle body.

FIG. 1 depicts the engine mount 10 in isolation prior to installation ina vehicle. In the present embodiment, with the mount installed, thedistributed support load of the power unit will be input in the axialdirection of the mount (the vertical direction in FIG. 1). Consequently,with the mount in the installed state, the first mounting member 12 andthe second mounting member 14 will undergo displacement towards oneanother in the axial direction due to elastic deformation of the mainrubber elastic body 16. Also, in the installed state the vibrationprimarily targeted for damping will be input approximately in the axialdirection of the mount. In the discussion following, unless indicatedotherwise, the vertical direction shall refer to the axial direction ofthe mount, which is also the vertical direction in FIG. 1.

The engine mount 10 according to the embodiment is a vibration dampingdevice of fluid filled type whose interior is filled with anon-compressible fluid. It employs a known structure such as that taughtin JP-A-2005-172202, for example, and as such need not be discussed indetail herein. The first mounting member 12, which is of generallycircular disk shape or circular cylindrical shape, is disposed spacedapart at a first opening (the upper opening in FIG. 1) of the secondmounting member 14 of tubular shape, with a main rubber elastic body 16of truncated conical shape disposed between the two members 12, 14. Theouter peripheral face of the first mounting member 12 is bonded byvulcanization to the small-diameter end of the main rubber elastic body16, while the inner peripheral face of the second mounting member 14 isbonded by vulcanization to the outside face at the large-diameter end ofthe main rubber elastic body 16 so that the first mounting member 12 andthe second mounting member 14 are elastically linked, with one openingof the second mounting member 14 covered fluid-tightly by the mainrubber elastic body 16. While not illustrated in the drawing, a covermember will be disposed over the other opening of the second mountingmember 14 so that this opening is covered fluid-tightly by the covermember.

With this arrangement, the inside of the second mounting member 14 isclosed by the main rubber elastic body 16 and the cover member, therebydefining a pressure-receiving chamber whose wall is partiallyconstituted by the main rubber elastic body 16. The pressure-receivingchamber gives rise to fluctuations in pressure in response to elasticdeformation of the main rubber elastic body 16. As taught in JP2005-172202, the cover member is partially formed of a rubber film, sothat it will be possible to adjust the pressure fluctuations within thepressure-receiving chamber through elastic deformation of the rubberfilm per se, or through forced excited displacement of the rubber filmusing an electromagnetic actuator or the like, to dynamically controlthe pressure fluctuations within the pressure-receiving chamber.

Furthermore, a readily elastically deformable diaphragm 22 is disposedas a flexible film so as to cover the outside of the main rubber elasticbody 16, whereby an equilibrium chamber, which readily allows change involume in response to elastic deformation of the diaphragm 22, is formedto the opposite side of the main rubber elastic body 16 from thepressure-receiving chamber. Specifically, the diaphragm 22 lies exposedto the outside of the mount unit. The pressure-receiving chamber and theequilibrium chamber are filled with a non-compressible fluid such aswater, an alkylene glycol, a polyalkylene glycol, or the like. Betweenthe pressure-receiving chamber and the equilibrium chamber is formed anorifice passage through which the chambers communicate with each other.The resonance frequency of the fluid induced to flow through the orificepassage will be tuned to that of the vibration being damped.

In particular, a mounting piece 24 is integrally formed in the upper endsection of the first mounting member 12. A fastening bolt is passedthrough a through-hole 26 bored through the mounting piece 24 and isfastened by being screwed into a mounting member on the power unit side.A mounting bracket 28 of tubular contours is fastened to the opening onthe other end (the lower end in FIG. 1) of the second mounting member14, and this mounting bracket 28 is fastened to a mounting member on thevehicle body side with bolts or the like. With this arrangement, theengine mount 10 is installed in the vehicle so as to be interposedbetween the power unit and the vehicle body and providevibration-damping support of the power unit on the vehicle body.

In this installed state, input of vibration across the first mountingmember 12 and the second mounting member 14 will give rise to relativepressure fluctuations between the pressure-receiving chamber and theequilibrium chamber. This ensures a sufficient level of flow of fluidthrough the orifice passage, thereby affording vibration damping actionbased on the flow effects, such as the resonance effect, of the fluid.

A flanged portion 30 which flares outward in the axis-perpendiculardirection is integrally formed at one end (the upper end in FIG. 1) ofthe second mounting member 14. The stopper member 18 is fastened to thisflanged portion 30.

As illustrated in FIGS. 2-4, the stopper member 18 includes a strikeplate portion 32 of generally rectangular plate shape extending in theaxis-perpendicular direction, as well as a pair of leg portions 34 ofgenerally rectangular plate shape which extend downward from either endof the strike plate portion 32, giving the fitting an arched shapeoverall. The connecting regions between the strike plate portion 32 andthe leg portions 34 where the upper ends of the leg portions 34 areintegrally formed with the ends of the strike plate portion 32 aresmoothly curving.

The lower ends of the leg portions 34 bend into rectangular plate shapeextending approximately parallel to the strike plate portion 32, andtheir lower ends are perforated by through-holes 36. The distanceseparating the opposed faces of the pair of leg portions 34 will begreater than the outside dimensions of the diaphragm 22. The heightdimension of the leg portions 34 will be sufficiently greater than theheight dimension from the flanged portion 30 of the second mountingmember 14 to the first mounting member 12 of the mount main unit.

Support panel portions 38 are integrally formed respectively along bothedges of the stopper member 18 in the direction of its width (thevertical direction in FIG. 3 or the sideways direction in FIG. 4). Thesupport panel portions 38 have flat plate shape extending upward fromthe widthwise edges of the stopper member 18 and extend with generallyunchanging height along the entire widthwise edge. Specifically, in thestopper member 18, the pair of support panel portions 38, 38 positionedin opposition on the width direction, the strike plate portion 32, andthe pair of leg portions 34, 34 together cooperate to define a detainingslot 40 of generally unchanging recessed cross section which opens tothe outside of the stopper member 18 and which extends continuouslythrough the pair of leg portions 34, 34 and the strike plate portion 32situated between them.

In the present embodiment in particular, a positioning channel 33 isformed at the center of the distal edge of each of the support panelportions 38 which rise up from either edge of the strike plate portion32 in its width direction (the vertical in FIG. 3) and extendapproximately parallel to the strike plate portion 32. The positioningchannels 33 are formed by notching the distal edge of the support panelportion 38 to a prescribed depth dimension; the basal face of thepositioning channel 33 will extend approximately parallel to the strikeplate portion 32, with its ends in the lengthwise direction (sideways inFIGS. 2 and 3) situated above widthwise edge portions of the strikeplate portion 32 at locations thereof located inward from the connectingsections with the leg portions 34. By forming such positioning channels33 in the support panel portions 38, stepped faces 35, 35 which aredefined by the lengthwise end faces of the positioning channel 33 willbe formed on the distal edge face of the support panel portion 38. Thestepped faces 35 are inclined upward from the basal face of thepositioning channel 33, and outward in the lengthwise direction of thepositioning channel 33.

With the first mounting member 12 and the diaphragm 22 of the mount mainunit positioned slipped between the pair of leg portions 34, 34 of thestopper member 18 having the above structure, the lower ends of the legportions 34 are juxtaposed against the flanged portion 30 of the secondmounting member 14, and fastening bolts 42 which project from theflanged portion 30 are passed through the through-holes 36 in the legportions 34 and fastened screwed thereon using fastening nuts. Thestopper member 18 is thereby fastened onto the flanged portion 30 of thesecond mounting member 14, with the stopper member 18 positioned spacedapart outwardly from the first mounting member 12 and the diaphragm 22;and with the strike plate portion 32 of the stopper member 18 positionedin opposition to the upside of the first mounting member 12 and facingit across a gap of prescribed distance.

Meanwhile, as depicted in FIGS. 5-15, the heat insulator 20 is formedfrom rubber elastic material, and includes a first film portion 44, asecond film portion 46, a center connector plate portion 48, and a pairof outside connector plate portions 50, 50, giving it an overall shaperesembling an inverted cup open downward.

The first film portion 44 has hollow, generally quarter-sphericalcontours, and a plurality of window portions 52 (two in the presentembodiment) formed at appropriate locations in the peripheral wallsection.

The second film portion 46 has a pouch shape of smaller width dimensionin comparison with the first film portion 44, and a large window portion54 of cutout form situated in its center section. A radiator plate 56 oftabular form projects outward from the peripheral wall section of thesecond film portion 46.

This first film portion 44 and second film portion 46 are positioned inopposition spaced apart by a prescribed distance in the width direction(the vertical in FIGS. 6 and 7), with the center connector plate portion48 and the pair of outside connector plate portions 50, 50 of generallyrectangular plate shape disposed between their opposed faces, and withthe widthwise ends of the connector plate portions 48, 50 are integrallyformed with the inner peripheral edge portion of the first film portion44 and the inner peripheral edge portion of the second film portion 46.Thus, the first film portion 44 and second film portion 46 are connectedto each other through the center and outside connector plate portions48, 50.

In the present embodiment in particular, the center connector plateportion 48 is situated at the center in the perpendicular direction (thesideways direction in FIGS. 6 and 7) to the direction of opposition ofthe first film portion 44 and second film portion 46, therebyconstituting the center section of the heat insulator 20. The outsideconnector plate portions 50 are positioned at locations spaced apartoutwardly from the center connector plate portion 48 in theaxis-perpendicular direction, thereby respectively constituting portionsof the peripheral wall section of the heat insulator 20. The centerconnector plate portion 48 has a generally rectangular plate shape whoselength dimension is smaller than the length dimension of the strikeplate portion 32 of the stopper member 18, while the outside connectorplate portions 50 have a generally rectangular plate shape whose lengthdimension is smaller than the length dimension of the center connectorplate portion 48.

At the inner peripheral edges of the first film portion 44 and thesecond film portion 46 in the heat insulator 20, there are formedplate-shaped mating plate portions 60 which project outward withgenerally unchanging height dimension throughout. This pair of matingplate portions 60, 60 are positioned in opposition spaced apart by aprescribed distance in the direction of opposition of the first filmportion 44 and the second film portion 46. Thus, in the heat insulator20, the pair of mating plate portions 60, 60, and the center connectorplate portion 48 as well as the pair of outside connector plate portions50, 50 which extend between the pair of mating plate portions 60, 60,cooperate to define an insertion slot 62 which opens to the outside ofthe heat insulator 20 and which extends continuously with generallyunchanging recessed cross section through zones reaching from the centersection to the peripheral wall section to either side. As will beunderstood from the above description, the pair of mating plate portions60, 60 are connected to one another by the center connector plateportion 48 and the pair of outside connector plate portions 50, 50. Thewidth and length dimensions of the insertion slot 62 will be slightlylarger than the width and length dimensions of the stopper member 18which includes the pair of support panel portions 38, 38.

In each mating plate portion 60, a center hook portion 64 constituting acatch hook portion is provided in the section thereof connecting withthe center connector plate portion 48, and outside hook portions 66constituting catch hook portions are provided in the sections of thereofconnecting with the outside connector plate portions 50. In other words,a pair of the center hook portions 64, 64 will be positioned inopposition spaced apart in the width direction of the center connectorplate portion 48, in the center of the bottom part of the heat insulator20. Additionally, pairs of the outside hook portions 66, 66 will bepositioned in opposition spaced apart in the width direction of theoutside connector plate portions 50 in a peripheral wall section of theheat insulator 20, and positioned in opposition to either side of thecenter of the heat insulator 20 along an axis lying in theaxis-perpendicular direction.

The center hook portions 64 and the outside hook portions 66 are eachcomposed of a horizontal wall portion 68 of rectangular plate shapeextending inward in the width direction from the upper edge of themating plate portion 60, and a vertical wall portion 70 of rectangularplate shape extending downward or inward from the inside edge of thehorizontal wall portion 68. The length dimensions of the center hookportions 64 and the outside hook portions 66 will be approximately equalin size to the length dimensions of the center connector plate portion48 and the outside connector plate portions 50, so that the lengthdimension of the center hook portions 64 is larger than the lengthdimension of the outside hook portions 66.

In the present embodiment in particular, in the center hook portions 64,the thickness dimension of the horizontal wall portion 68 will beidentical to or slightly smaller than the thickness dimension of themating plate portions 60, whereas the thickness dimension of thevertical wall portion 70 will be sufficiently larger than the thicknessdimension of the mating plate portions 60. Thus, the thickness dimensionof the vertical wall portion 70 of the center hook portions 64 issufficiently larger than the thickness dimension of the horizontal wallportion 68. On the other hand, the thickness dimension of the horizontalwall portion 68 and the thickness dimension of the vertical wall portion70 of the outside hook portions 66 will both be approximately the sameas the thickness dimension of the mating plate portions 60.

Furthermore, the vertical wall portion 70 of the center hook portion 64is situated in opposition to and spaced apart in the width directionfrom the mating plate portion 60 by a distance equal to the widthdimension of horizontal wall portion 68, and extends parallel to themating plate portion 60. The height dimension of the vertical wallportion 70 is of size such that its projecting distal edge section whichextends towards the respective connector plate portion 48, 50 from theinside edge of the horizontal wall portion 68 situated at the sameheight as the upper edge section of the mating plate portion 60 does notcome into contact against the connector plate portion 48, 50. In thepresent embodiment in particular, the vertical wall portion 70 on theside thereof situated in opposition to the mating plate portion 60 hasan inside edge of tapered contour of decreasing width dimension goingfrom its axial medial section towards its projecting distal end section.The dimension of the center hook portions 64 in the lengthwise direction(sideways in FIGS. 7 and 8) is slightly smaller than the dimension inthe lengthwise direction (sideways in FIGS. 2 and 3) of the positioningchannel 33 formed in the support panel portions 38 of the stopper member18, in other words, slightly smaller than the distance separating thepair of stepped faces 35, 35.

In the heat insulator 20, the center connector plate portion 48 with theintegrally formed center hook portions 64 and the outside connectorplate portions 50 with the integrally formed outside hook portions 66are disposed spaced apart in the direction perpendicular to the widthdirection (i.e. the lengthwise direction) of the connector plateportions 48, 50. Thus, the center hook portion 64 and the respectiveoutside hook portions 66 formed on each mating plate portion 60 arepositioned in opposition spaced apart by prescribed distances in thelengthwise direction. Additionally, lightening holes 72 of rectangularshape are formed between the center hook portion 64 and the respectiveoutside hook portions 66, at locations between the center connectorplate portion 48 and the respective outside connector plate portions 50.

An integrally vulcanization molded stopper rubber 58 which projectsdownward is formed on the center connector plate portion 48 of the heatinsulator 20. This stopper rubber 58, which constitutes a cushioningrubber, is composed of several tabular portions of rectangular plateshape stacked in the axial direction with their outside dimensionbecoming gradually smaller towards the distal end in the direction ofprojection. The stopper rubber 58 is positioned eccentrically towardsthe second film portion 46 to one side in the width direction (upward inFIG. 6) on the bottom center of the heat insulator 20.

To the mount main unit to which the stopper member 18 has been fastened,the heat insulator 20 having the above structure is now attached throughinsertion between the inside of the arch-shaped stopper member 18 andthe first mounting member 12 and the diaphragm 22, and the stoppermember 18 is inserted within the insertion slot 62. The center connectorplate portion 48 of the heat insulator 20 is juxtaposed from the innerface side against the strike plate portion 32 of the stopper member 18,and the outside connector plate portions 50 of the heat insulator 20 arejuxtaposed from the inner face side against the leg portions 34 of thestopper member 18.

Furthermore, the center hook portions 64 and the outside hook portions66 of the heat insulator 20 undergo elastic deformation expanding thedistance between the mating plate portion 60 and the respective verticalwall portions 70 of the hook portions 64, 66, whereupon the verticalwall portion 70 passes the support panel portion 38 of the stoppermember 18 from the outside in the width direction or from the outside inthe axial direction, and becomes positioned within the detaining slot 40situated to the inside of the support panel portion 38. Additionally,the support panel portions 38 projecting from the strike plate portion32 of the stopper member 18 slip between the mating plate portion 60 andthe vertical wall portion 70 of the center hook portions 64, with theupper edge portion of the support panel portion 38 becoming positionedin opposition to the horizontal wall portion 68. Additionally, thesupport panel portions 38 projecting from the leg portions 34 of thestopper member 18 slip between the mating plate portion 60 and thevertical wall portion 70 of the outside hook portions 66, with the upperedge portion of the support panel portion 38 becoming positioned inopposition to the horizontal wall portion 68. It is not particularlycritical whether the horizontal wall portion 68 of the hook portions 64,66 and the upper edge portion of the support panel portion 38 are inabutment or spaced apart. The connector plate portions 48, 50 of theheat insulator 20 are juxtaposed against the stopper member 18, and thesupport panel portions 38 are clasped between the vertical wall portion70 of the hook portions 64, 66 and the mating plate portion 60, wherebythe heat insulator 20 is supported securely on the stopper member 18.Namely, a structure for supporting the heat insulator 20 on the stoppermember 18 is provided by engaging the hook portions 64, 66 with bothwalls of the detaining slot 40.

In the present embodiment in particular, the center hook portions 64 fitmated within the positioning channels 33 of the support panel portions38, and the horizontal wall portion 68 of the center hook portions 64 ispositioned in opposition to, and either abutting or spaced apart from,the basal face of the positioning channel 33, while the lengthwise endfaces of the center hook portions 64 are positioned in respectiveopposition to the stepped faces 35 of the stopper member 18. By makingthe lengthwise dimension of the center hook portions 64 slightly smallerthan the distance separating the pair of stepped faces 35, 35, when thecenter section of the center hook portion 64 is positioned in the centerbetween the opposed faces of the pair of stepped faces 35, 35, whilestrictly speaking there is separation between the end faces of thecenter hook portion 64 and the stepped faces 35, the distance separatingthese end faces and the stepped faces 35 is small enough to be ignored,and the end faces of the center hook portion 64 can be considered toessentially abut the stepped faces 35.

The automotive engine mount 10 according to the present embodiment isnot limited to that depicted by way of example herein. For example, thelengthwise dimension of the center hook portions 64 could instead belarger than the distance separating the pair of stepped faces 35, 35 sothat when the center hook portion 64 is fitted into the positioningchannel 33, the center hook portion 64 will undergo compressivedeformation, while the end faces of the center hook portion 64 come intoabutment against the stepped faces 35.

With this arrangement, deformation of the center hook portion 64 in itslengthwise direction with respect to the support panel portions 38 ofthe stopper member 18 will be restricted, and the center section of theheat insulator 20 will be positioned on the strike plate portion 32 inthe center section of the stopper member 18, securely supported thereonwith the support panel portions 38 clasped by the center hook portions64. In association with this positioning of the center section of theheat insulator 20, the peripheral wall sections of the heat insulator 20will be positioned against the pair of leg portions 34 situated to theoutside peripheral side of the stopper member 18, securely supportedthereon with the support panel portions 38 clasped by the outside hookportions 66. As a result, the heat insulator 20 will be retained whilepositioned spaced apart by a prescribed distance to the outside of thefirst mounting member 12 and the diaphragm 22 and while positioned so asto cover the first mounting member 12 and the diaphragm 22 and securedto the mount main unit via the stopper member 18.

With the heat insulator 20 and the stopper member 18 fastened together,due to the fact that the center connector plate portion 48 of the heatinsulator 20 is juxtaposed against the strike plate portion 32 of thestopper member 18, the stopper rubber 58 which projects from the centerconnector plate portion 48 will be positioned along the strike plateportion 32 on the side thereof which faces towards the first mountingmember 12, and will project towards the first mounting member 12 fromthe stopper member 18 side.

Assembly of the heat insulator 20 onto the mount main unit may also beaccomplished by fastening it to the mount main unit to which the stoppermember 18 has been previously fastened. Alternatively, the heatinsulator 20 may be fastened to the stopper member 18 prior to beingfastened to the mount main unit, and the stopper member 18 then fastenedto the mount main unit.

In the automotive engine mount 10 equipped with the heat insulator 20having the above structure, if a large load is input in the rebounddirection across the first mounting member 12 and the second mountingmember 14 inducing appreciable displacement of either of the two members12, 14 away from the other, the first mounting member 12 and the strikeplate portion 32 of the stopper member 18 will strike each other via thestopper rubber 58 which has been integrally formed with the heatinsulator 20, thereby providing cushion-wise limitation of displacementof the members 12, 14 in the rebound direction. As a result, excessivedeformation of the main rubber elastic body 16 will be prevented, anddurability will be improved. Moreover, as will be apparent from thepreceding description, the rebound stopper mechanism of the firstmounting member 12 and the second mounting member 14 according to thepresent embodiment is constituted to include the stopper member 18 andthe stopper rubber 58.

This kind of automotive engine mount 10 will be positioned at a locationwhere it tends to be exposed to radiant heat from the engine, but sincethe outside faces of the first mounting member 12 and the diaphragm 22are spacedly covered by the heat insulator 20, as a matter of course themain rubber elastic body 16 situated in the interior of the mount mainunit, as well as the diaphragm 22, will be well protected by the heatinsulator 20 thereby advantageously affording improved durability of thediaphragm 22 and the main rubber elastic body 16.

Since the heat insulator 20 provided with the stopper rubber 58 isfabricated as a separate component from the stopper member 18,independently design modifications can respectively be made to thestopper rubber 58 and heat insulator 20 on the one hand, and the stoppermember 18 on the other, thus affording sufficient freedom in design ofthe heat insulator 20 and the stopper rubber 58, and of the stoppermember 18.

Since the stopper rubber 58 is integrally formed with the heat insulator20, vulcanization molding of the stopper rubber 58 and the heatinsulator 20 can be accomplished with a single mold, thereby affordingadvantages in terms of manufacturing process efficiency and lower cost.

Furthermore, in the present embodiment, because positioning of the heatinsulator 20 on the stopper member 18, and hence on the mount main unit,is accomplished through abutment of the end faces of the center hookportions 64 against the stepped faces 35 of the support panel portions38, the positioning structure is a simple one. Moreover, the end facesof the center hook portions 64 and the stepped faces 35 of the supportpanel portions 38 will be maintained in the abutting state with the unitinstalled in an automobile, thereby preventing the heat insulator 20from shifting out of place with respect to the mount main unit.

Furthermore, since the center hook portions 64 and the outside hookportions 66 integrally formed with the heat insulator 20 are used tofasten it to the stopper member 18, the fastening structure is simplerthan one employing bolts or the like for fastening, and therefore theproblem of a more complicated overall structure inclusive of thepositioning structure discussed above can be advantageously eliminated.

Moreover, in the present embodiment, the mating plate portions 60 of theheat insulator 20 and the support panel portions 38 of the stoppermember 18 respectively extend continuously from one peripheral edgeportion (end portion) through the center section and on to the otherperipheral edge portion (end portion), with the support panel portions38 and the mating plate portions 60 juxtaposed in the width directionalong their entirety. Specifically, the strike plate portion 32 and thepair of leg portions 34 of the stopper member 18 fit inserted into theinsertion slots 62 which are defined through cooperation by the pair ofmating plate portions 60, 60 of the heat insulator 20. Therefore, theheat insulator 20 will be supported on the stopper member 18 with morestability.

Furthermore, in the present embodiment, there is employed a structurewherein the center hook portions 64 and the outside hook portions 66 areconstituted to include the horizontal wall portion 68 which extendsinward in the width direction from the upper edge of the wall of theinsertion slot 62 (the mating plate portion 60) and the vertical wallportion 70 which extends towards the bottom of the insertion slot 62from the inside edge of the horizontal wall portion 68, and wherein theupper edge section of the detaining slot 40 of the stopper member 18(the upper edge of the support panel portion 38) fits inserted to theinside of the horizontal wall portion 68 and the vertical wall portion70 so that the center hook portions 64 and the outside hook portions 66are detained by the two walls of the detaining slot 40 (the pair ofsupport panel portions 38, 38). With this structure, the hook portions64, 66 will be engaged by the walls of the detaining slot 40 such thatthe hook portions 64, 66 are enrolled by the walls of the detaining slot40, thus more advantageously providing stable support of the heatinsulator 20.

Furthermore, in the present embodiment, the vertical wall portion 70 ofthe center hook portion 64 is thicker than the horizontal wall portion68. With such a structure, the wall of the detaining slot 40 can beclamped at a satisfactory level of force in the axis-perpendiculardirection by the vertical wall portion 70, thus advantageously improvingthe stability of support of the heat insulator 20. Additionally, upwardbending of the vertical wall portion 70 during vulcanization molding ofthe hook portion 64 or during imposition of the hook portion 64 againstthe wall of the detaining slot 40 can be prevented. Meanwhile, since thehorizontal wall portion 68 is thinner than the vertical wall portion 70,good elastic deformation behavior on the part of the hook portion 64will be assured, and it will be possible to advantageously avoid greaterdifficulty in the operation of assembling the heat insulator 20 with thestopper member 18 owing to a thicker vertical wall portion 70.

Moreover, in the present embodiment, the distal edge section of thevertical wall portion 70 of the center hook portion 64 has a taperingshape which becomes thinner towards the bottom of the insertion slot 62.With such a structure, it is possible to reduce or prevent the distaledge section of the vertical wall portion 70 from hitting the strikeplate portion 32 or the basal end sections of the leg portions 34 at thewall of the detaining slot 40 of the stopper member 18, providingfurther improvement in ease of the assembly operation and stability inthe assembled state.

Furthermore, in the present embodiment, lightening holes 72 are formedbetween the center hook portions 64 and the outside hook portions 66 ofthe heat insulator 20, with the connecting sections of the leg portions34 with the strike plate portion 32 of the stopper member 18 beingsituated at these lightening holes 72. Such a structure obviates theneed for the surfaces of the connecting sections to be juxtaposedagainst the outer peripheral faces between the center hook portions 64and the outside hook portions 66, thereby eliminating poor matingbetween the strike plate portion 32 and the center hook portions 64 orpoor mating between the leg portions 34 and the outside hook portions 66which may result where connecting section surfaces and the outsideperipheral surfaces of the hook portions 64, 66 of mutually differentshape are forcibly mated together. As a result, stability of assembly ofthe heat insulator 20 to the stopper member 18 may be improved. Also,the surfaces of the connecting sections need not be designed withespecially high precision in order to fit precisely juxtaposed againstthe outer peripheral faces between the center hook portions 64 and theoutside hook portions 66, thereby affording an easier manufacturingprocess. Consequently, where the stopper rubber 58 is integrally formedwith the heat insulator 20 stably supported on the stopper member 18 asdescribed above, in association with support of the heat insulator 20 onthe stopper member 18 the stopper rubber 58 will be disposed on thedesired strike plate portion 32 of the stopper member 18, and therebydisposed reliably on the strike plate portion 32 without the use of anyspecial fastening components, while preventing it from shifting out ofposition.

Moreover, through juxtaposition of the heat insulator 20 against thestopper member 18 from the inner side, the stopper rubber 58 mayadvantageously be projected towards the first mounting member 12 whileensuring room to the inside of the stopper member 18 to permitadvantageous setting of the distance between the opposing faces of thestopper rubber 58 and the first mounting member 12.

For this reason, the design of the stopper rubber 58, the stopper member18, and the heat insulator 20 can be modified advantageously accordingto the required stopper action and heat insulating action, to attainhigh levels of both the desired stopper action and heat insulatingaction.

Additionally, because both the center section and the peripheral sectionof the heat insulator 20 are supported on the stopper member 18, it willbe possible for example to avoid stress concentrations from occurring inthe heat insulator 20 due to relative displacement of the first mountingmember 12 and the second mounting member 14, such as can occur where thecenter section of the heat insulator 20 is supported on the firstmounting member 12 side while the peripheral section of the heatinsulator 20 is supported on the second mounting member 14 side. As aresult it will be possible to improve durability of the heat insulator20 and of the stopper rubber 58 which is integrally formed with the heatinsulator 20.

While the present invention has been described in detail hereinabovethrough certain preferred embodiments, these are merely illustrative andthe present invention should not be construed as limited in any way tothe specific disclosure of the embodiments herein. Variousmodifications, alterations, and improvements thereto will be apparent tothe practitioner of the art, and embodiments incorporating the sameshall naturally be considered to fall within the scope of the presentinvention insofar as they do not depart from the spirit thereof.

For example, the shape, size, structure, number, placement, and otheraspects of the stopper rubber 58, the stopper member 18, the heatinsulator 20, the mount main unit and so on are not limited to thosetaught herein by way of example. Specifically, whereas in the precedingembodiment a single stopper rubber 58 is provided positionedeccentrically from the center of the center connector plate portion 48of the heat insulator 20, it would also be possible for the stopperrubber 58 to be situated in the center, or to provide more than onestopper rubber, depending on the required stopper capability,manufacturability, and other considerations.

Also, whereas in the preceding embodiment the heat insulator 20 includesa first film portion 44 and second film portion 46 pair of pouch shape,depending on considerations such as the required heat insulating actionand manufacturability, the second film portion 46 may have flat contoursso as to be juxtaposable along mating plate portion 60 of the stoppermember 18, as shown for example in FIGS. 16 through 18. In thedescription referring to FIGS. 16 through 18, components and regionssubstantially identical in structure to the preceding embodiment areassigned identical symbols in the drawings and are not discussed in anydetail.

Furthermore, whereas in the preceding embodiment the peripheral wallsection of the heat insulator 20 is fastened to the leg portions 34, 34of the stopper member 18 through the agency of the pair of outside hookportions 66, 66, it would be possible to fasten to only one of the legportions 34 using one of the outside hook portions 66.

Moreover, whereas in the preceding embodiment the heat insulator 20 issupported on the stopper member 18 with the catch hook portionsconstituted by the center hook portions 64 and the outside hook portions66 of the heat insulator 20 detained by the walls of the detaining slot40 of the stopper member 18, the catch hook portions and the detainingslot 40 are not essential elements. For example, it would be acceptableinstead to juxtapose the center section and the peripheral wall sectionof the heat insulator 20 against the strike plate portion 32 and the legportions 34 of the stopper member 18 from the inner face side, and toaffix them together using adhesive, bolts, or the like.

Moreover, whereas in the preceding embodiment, positioning channels 33of notched shape are formed in the distal edge section of the supportpanel portions 38 with stepped faces 35 being defined by the lengthwiseend faces thereof, the positioning channels 33 and the stepped faces 35are not essential elements.

Furthermore, whereas the preceding embodiment describes implementing thepresent invention in a liquid system engine mount 10 having an internalpressure-receiving chamber, equilibrium chamber, and orifice passage,and filled inside with a noncompressible fluid, the invention is notlimited thereto and could of course be implemented analogously, forexample, in a solid system vibration damping device in which a firstmounting member and a second mounting member are simply linked by a mainrubber elastic body.

Additionally, whereas the preceding embodiment describes implementingthe present invention in an automotive engine mount by way of specificexample, it would be possible to implement the invention analogously invarious other kinds of vibration damping devices that requireinstallation of a stopper mechanism and a heat insulator.

1. A vibration damping device having a rubber heat-insulating covercomprising: a first mounting member fixable to one of componentsconnected together in a vibration damping fashion; a second mountingmember fixable to an other of the components; a main rubber elastic bodyelastically connecting the first and second mounting members; a stoppermember of arched shape which includes a pair of leg portions at eitherend of a strike plate portion extending in an axis-perpendiculardirection, the stopper member being attached with lower ends of the pairof leg portions fastened to the second mounting member so as to projectoutward from the first mounting member in order to effect relativepositioning of the strike plate portion and the first mounting member; acushioning rubber disposed on the strike plate portion on a face thereofin opposition to the first mounting member, to constitute a reboundstopper mechanism for cushion-wise limitation of an amount ofdisplacement of the first mounting member and the second mounting memberin a direction of mutual separation, through striking of the firstmounting member and the strike plate portion via the cushioning rubber;and a rubber heat-insulating cover for covering an outside face of themain rubber elastic body with a gap therebetween, disposed overlying themain rubber elastic body from the first mounting member side, whereinthe rubber heat-insulating cover is formed as a separate component fromthe stopper member and is disposed between the stopper member and themain rubber elastic body while affixing the rubber heat-insulating coverto the stopper member with a center section of the rubberheat-insulating cover juxtaposed from an inner face side against thestrike plate portion of the stopper member to be supported by the strikeplate portion, and with a peripheral wall section of the rubberheat-insulating cover juxtaposed from the inner face side against theleg portions of the stopper member to be supported by the leg portions,and the cushioning rubber is integrally formed with the center sectionof the rubber heat-insulating cover supported on the strike plateportion, and projects towards the first mounting member.
 2. Thevibration damping device according to claim 1, wherein catch hookportions are integrally formed in the center section and the peripheralwall section of the rubber heat-insulating cover, and a detaining slotwhich opens towards an outside is formed in the strike plate portion andthe pair of leg portions of the stopper member so that a structure forsupporting the rubber heat-insulating cover on the stopper member isprovided by engaging the catch hook portions with both walls of thedetaining slot.
 3. The vibration damping device according to claim 1,wherein the rubber heat-insulating cover has an inverted cup shape andincludes an insertion slot formed extending along both peripheral wallportions from a bottom portion on an outside face of the rubberheat-insulating cover, and the stopper member is fitted into theinsertion slot.